I can't answer your question so I'll ask one of my own! Are you sure the Sprinters have two roof vents or is one of them the roof air conditioner?

 

Yes, I'm sure they are both vents. Most of them state the same reason Petersampogna gave; one to draw air in,and the other to push it out. I am just curious as to why people with Transits don't do this.

 

Does the Transit have more passive venting, thereby mitigating the need for two fans?

No.

 

Any air leaving the interior needs to be replaced, options: open a window, second roof vent or floor vent.

 

I have two vents in 5 sprinter’s and one promaster.
One blowing in one blowing out is fantastic for cooling. I have even opened side door and blown both in


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My next build is a transit and it will have two vents and roof air. Oh and the new vents run closed and are ceiling fans that keep the temperature uniform in winter and summer

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Sounds like you like plenty of air movement. What fans are you planning to use?

 

Two fans would be nice, one is still pretty effective. I installed a slider window with a screen to provide an inlet for fresh air minus mosquitoes.

Just be sure to finalize your floorplan before cutting holes, my fan ended up with a bulkhead right in the middle of it. Works fine, just looks weird to me.

Also your fan location will limit the solar panel layout etc.

 

Planning one one Fantastic fan for general exhaust and a ventline for the wet bath. Makeup air will be either through the awning style windows or the Dometic Midi Heki opening skylight.

 

There are a few of us that have two vents, only one is fanless and forward in the floor, with a path to the one at the rear that passes the hot parts, like the back of the fridge or the inverter so that it aids convection of heat away from those devices.

The single fan in the roof can move enough air to completely replace all the air in the van several times an hour. Many find that convection alone with no fan running is sufficient to keep the temperatures in the van at the same level as the ambient air temp outside.

There may be valid reasons that folks use two fans, but it probably is more about cooking or odor control, or something other than removing heat.

As mentioned before, get your floor plan worked out, then think about how you will use it. Then change it based upon what you discover. Think about it some more and find the other things you may have not considered. Then, start thinking about fans and ventilation and where to make the holes.

 

I have used both vantastic and maxair. My preference now is maxair

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Thanks all! I was planning to use a single roof fan, as is plenty to turn over the air quickly enough. I will also heed Travlin's advice to allow for air passage for at least the fridge. I have a wine fridge and drink fridge next to each other under my counter at home, and I know how much heat they generate.

As far as the two fans on Sprinters, I did not realize the difference in roof shape and rib placement. Available roof real estate makes perfect sense to me. They do it because they can, and still have enough space for solar panels!

 

As TRAVLIN implied, you need 2 vents but only one on the roof. I wanted to keep the roof uncluttered for maximum use of the roof rack, so like many others, I have a vent in the floor and a MaxAir on the top.

IMHO, 2 in the roof is expensive, cluttering and inefficient - it doesn't force movement of all the air, just the layer closest to the ceiling.

 

Can you share the details on your floor vent? That could solve my problem.

 

Go with two. I'll bee adding a second one shortly.

 

Heck, go with three. That way instead of replacing all the air in the van every 30 seconds (Maxxfan on high - 900CFM; volume of Mid/LongWB ~450 ft.cu.) you could replace all the air with outside ambient temp air every 10 seconds. Could anyone not see the advantage of this?

I could put one more Maxxfan on each side and have red and yellow streamers coming off them so it might look like flames coming out of afterburners. >

Even the A-Team would be jealous.

 

Two Fans

I'm preparing to build out a 2018 130 MR Wagon (fixed glass all around). I'm planning to use two Maxxair fans; one for inflow and one outflow. I've looked at replacing one of the side windows with one that opens/has screen for inflow, but the cost is nearly $1,000. The fans are only $325 each.
Anyone have any other suggestions?
Thanks for your time!

 

Thank you orton!

 

Here's another

https://www.fordtransitusaforum.com...amper-vans-conversions/53137-travlin-van-build-van-der-loosed-3.html#post930634

This is based on Orton's idea, and is using parts from Amazon sold for woodworking vacuum systems to create a valve and a filter for the floor vent.

 

I installed a single MaxxAir fan roughly in the middle of the cargo area roof (to the rear of the largest rib span on a long wheelbase extended). As replies above mentioned, having an inlet for fresh air is necessary for the fan to move fresh air through the van, but this can be done in 3 primary ways:

Two roof fans: One front and one rear provides an in/out cross vent over the length of the van. This is the Sprinter layout you described, and is an option for a van with no windows. This draws in the "warmest air"
Single roof fan and vented/screened windows: One fan drawing air from one or more windows. Key here is to have the fan and window(s) placed some distance apart to create a good airflow vs. "straight up". For example, fan at the far rear and windows up front, visa-versa, or windows at 4 corners and fan in the middle. I put my fan in the middle and have t-vent windows on the slider and opposite side as well as "bunk sliders" in the far rear. The fan can pull a lot of air, so it replaces the air quickly in this arrangement. I'm very happy with this setup.
Roof fan and floor vent: Theoretically draws the "coolest air" from under the van and also a good option for a van with no windows. I've read about challenges of managing road dust in the vent as well as some thoughtful designs on remote vent open/close and filters that you can find in this forum.

Having just enjoyed the maiden voyage this past weekend, air movement is a really important aspect of your build along with effective thermal/light blocking window coverings or a "no windows" option.

 

While I don't use roof fans while driving I have had 2 in all my vans since 2008 (6 vans) if it is 75 or below and your van is insulated it's is a joy. If you use the maxair which work ad ceiling fans then there is a double benefit of uniform head & air

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In this area it goes more or less from winter to hot with little 75 degree weather in between.

While I agree with the idea of venting hot air, I would just use a small blower and vent out another way rather than waste all of that roof real estate on an exhaust fan.

 

To each his own we work all day with heat from ultrasonics lights and grinders and it saves using roof air

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Had a crazy idea a few weeks ago. If the goal is to preserve roof space, how about a MaxxAir fan imbedded near the top of the rear door with the exhaust pointing down?
Anybody want to be the pioneer who cuts a hole in his door to see if it works?
Is there room above the window or window space if it’s all sheet metal?

 

This seems like a good thread to introduce a new 'most forward' vent adapter for the medium and high roof transits. This allows front vent to be moved forward so the front edge of the hole is up to the beam inside. The adapter is shaped to fit over the seam on the roof. This will allow for more space between the vents for a larger solar array. We are also now producing precise fit interior framing strips that are shaped to match the beams and roof curvature on the inside of the van. These are specific to each bay between the factory roof beams Our previous framing strips needed to be cut to fit but these new strips come precut and ready to install.

All the best,
Hein
DIYvan
541 490 5098

 

That looks great. Are there any issues with cutting through the seam?

 

We have a single MaxxFan in the back and these up front. Works great!

 

Q
Could a second max air vent create better airflow that may replace AC?
One vent by itself is unimpressive.

 

EDITED - Just realized that Hein (referenced below) is on this forum and already posted the info on the adapters and the design.



Hi all, I have a 148 HR. Two maxxair fans leave precious little space for solar panels on top. But I found a seller on eBay who created a CAD drawing showing how I can get 3 100W panels on the roof. They will come close to going over the sides so may look a little goofy, but it's a decent plan if you want 2 roof vents and at least 300 watts of solar.

Also important (and this is how I found him): He makes expanded PVC adapters that will ensure there are no gaps between your fan and the corrugations in the roof. He designed a new one for moving the front vent as far forward on the ford transit as possible. Be sure to message him about your application to ensure you get the right part for your application.

Ford Transit High & Mid Roof Vent Adapter | eBay

 

Did you happen to install the “most forward” adapter or come across anyone who has? I am curious if the cross-member makes the install more complicated.

EDITED - Just realized that Hein (referenced below) is on this forum and already posted the info on the adapters and the design.



Hi all, I have a 148 HR. Two maxxair fans leave precious little space for solar panels on top. But I found a seller on eBay who created a CAD drawing showing how I can get 3 100W panels on the roof. They will come close to going over the sides so may look a little goofy, but it's a decent plan if you want 2 roof vents and at least 300 watts of solar.

Also important (and this is how I found him): He makes expanded PVC adapters that will ensure there are no gaps between your fan and the corrugations in the roof. He designed a new one for moving the front vent as far forward on the ford transit as possible. Be sure to message him about your application to ensure you get the right part for your application.

Ford Transit High & Mid Roof Vent Adapter | eBay

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